In a principal aspect, the present invention relates to a counterbalance table, and more particularly, to a work table construction having an adjustable counterbalance force for an adjustable height work table platform.
In the manufacturing sector, manufacture of various products often requires assembly of components or a product at a work station on a work table. The assembly of a product is effected by artisans or workers at that work table station. Because of the different physical characteristics of individual workers as well as because of the need to adjust the height of the work table as a product is being assembled thereon, work tables are constructed so that their height can be easily changed. A feature associated with such work tables is the requirement to be counterbalanced so that varying weights or loads on the table can be easily supported at a work station and the work table platform can be easily moved upwardly or downwardly as necessitated. Thus, various mechanisms have been developed to enable work station tables to be counterbalanced to accommodate the load of work pieces thereon and to simultaneously permit adjustment of the height of the table.
Previously, very complicated articulated arms and gear mechanisms have been used to provide a counterbalancing construction for work tables. Such counterbalance systems require numerous parts which are formed in complicated operations and interact or fit together in a manner which requires rigid tolerances in the manufacturing operation. Thus, there has developed a need to provide an improved counterbalance table construction.
Briefly, the present invention comprises a counterbalance table of the type having a work table platform which is mounted on a stand having a fixed vertical leg with a telescoping leg projecting therefrom with the telescoping leg connected from the fixed leg to the underside of the work table or work platform. In practice, first and second spaced parallel leg systems support the opposite sides of a work table. The telescoping leg includes a rack thereon. A pinion is typically attached to the fixed leg. The pinion engages the rack and the pinions of the respective legs are attached so that the legs will move smoothly in unison even though they are spaced one from the other. A foot pedal actuated locking mechanism is provided to lock the pinions and thus lock the table at a fixed height, depending upon the telescopic extension of the telescoping legs within the fixed legs of the table support stand.
Four fluid actuated cylinders are provided to further support the work platform or work table. Two cylinders are provided in association with each of the vertical upstanding leg systems. One of the fluid cylinders may remain constantly engaged with the work table to provide a counterbalance force to support the weight of the table itself. Thus, the one fluid cylinder includes either a gas or liquid which is compressed and provides a counterbalance force to support the work platform or table. The remaining three fluid cylinders are optionally engaged with the underside of the work platform or work table. That is, a locking mechanism is provided which locks and retains the additional fluid cylinders in the locked position unless appropriately released. The additional cylinders may be of varying capacity to support a load on the work table. For example, from 30 pounds up to 200 pounds of carrying capacity may be provided by each cylinder. The lock mechanism is activated or deactivated only when the work table is in the lowered position to permit disengagement of a locking plate from the support cylinders. When the table is in the lowered position then, the cylinders may be retained in their locked position so as not to engage the table and provide a counterbalance force to the underside of the work platform or they may also be transferred to the unlocked position so as to engage the underside of the work platform table and thus provide a counterbalance force to a load on the table. Since there are three cylinders in the disclosed embodiment in addition to the cylinder which provides the normal counterbalance force for the work table itself, the choice of which of the three cylinders may be activated depends upon the counterbalance force required. A worker can thus accommodate very precisely, the counterbalance force required at the work station. One, two, or three cylinders may be activated to counterbalance a force due to the weight on the work table.
The system is designed so that the cylinders can be released or unlocked for counterbalancing only when the table is in its lowest position. Once the table moves upwardly from its lowest position, a cam mechanism locks the cylinders in their locked or unlocked position, thereby disabling the cylinders or enabling the cylinders. Once the counterbalance force is set, however, for a fixed load, the table can be easily moved up and down as needed by the worker. Also, the table can be easily locked and unlocked in various positions when loaded by locking the pinion or releasing the pinion.
Thus, it is an object of the invention to provide an improved counterbalance table.
It is a further object of the invention to provide a counterbalance table which permits adjustment of the force on the table in an easy and inexpensive manner and which is highly efficient, to counterbalance the weight of the table and the load thereon.
Yet a further object of the invention is to provide a counterbalance mechanism which is easy to assemble, easy to service, inexpensive and rugged.
Another object of the invention is to provide a counterbalance table which permits adjustment of the counterbalance force in order to accommodate various loads.
Another object of the invention is to provide a counterbalance table which includes a locking mechanism that locks the counterbalance table height at a fixed height, depending upon worker preference and wherein that locking mechanism is a mechanical mechanism.
Yet a further object of the invention is to provide a counterbalance mechanism which permits symmetrical arrangement of counterbalance forces on a work table or platform.
These and other objects, advantages and features of the invention will be set forth in the detailed description which follow.